The quantity and quality of nutrient supply during infancy has immediate consequences on growth, body composition, health, and well-being and has important long-term consequences on organ development and function, disease risks, as well as cognitive ability in later life.
In human breast milk (HBM), about 50% of the dietary calories are supplied as milk fat. Human Milk Fat (HMF) is composed of about 30-40 g/L lipids. Of those, approximately 98% are triglycerides, 0.3-1% phospholipids, and 0.4% cholesterol [WO05/051091, WO 06/114791].
(Dietary) lipids, such as those found in HBM, are indispensable for e.g. normal growth and development as major building blocks of cell membranes and tissues, and are e.g. important in signal transduction processes and in a variety of biochemical and biosynthetic pathways. Many lipids, and especially triglycerides, are part of human nutrition on a daily basis.
Triglyceride fats, or triglycerides, are the main energy source of newborn infants (Hamosh et al., Pediatrics 1985, 75 (suppl):146-150). In addition to providing 40% to 50% of the total calories in human milk or formula, triglycerides are essential to normal development since they provide fatty acids necessary for brain development, are an integral part of cell membranes, and are a vehicle for fat soluble vitamin and hormones in milk. Furthermore, these energy rich triglycerides can be stored in the body in nearly unlimited amounts in contrast to the limited storage capacity for carbohydrates and proteins.
The triglyceride composition of HMF is unique in its fatty acid composition and distribution. HMF is characterized in a total palmitic acid (C16:0) content of about 17-25%, of which about 70% are positioned at the sn-2 position of triglycerides [WO 05/051091]. Additionally, sn-1 and sn-3 positions are rich in unsaturated fatty acids, especially monounsaturated fatty acids, such as oleic acid (C18:1), which is of great importance to the infant's nutrition and development.
The sn-1 and sn-3 positions of vegetable fats are rich in saturated fatty acids and are thus not suitable for infant nutrition. Hence, advanced infant formulas include structured fats produced to mimic the unique structure and characteristics of HMF.
Phospholipids are an essential nutritional component of HBM. Although phospholipid composition remains constant and is not influenced by a mother's diet, the level of phospholipids in HBM changes with the age of the infant.
Phospholipids are composed of five major moieties: sphingomyelin (SM), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylinositol (PI). [Thompkinson D K et al. Comprehensive Reviews In Food Science And Food Safety 6:79-102 (2007)].
Some phospholipids, and especially those extracted from soybean, are used as dietary supplements and a variety of health benefits are associated with their intake. These benefits include the improvement of cognitive functions, improvement of memory and concentration, maintenance of cellular membrane composition, and contribution to general well-being. Phospholipids and lecithins are a source of choline and they enhance the bio-availability of other nutrients and therapeutics.
Poly-unsaturated fatty acid (PUFA) levels in HBM vary widely depending on the type of fat consumed by a mother. Still, compared to cow milk fat, a fairly broad spectrum of fatty acids and a high content of unsaturated fatty acids, particularly linoleic acid, are present in HBM. In formulae based on cow milk on the other hand, blends of vegetable oil are added to provide an adequate amount of PUFAs, including linoleic acid and others.
Also glycerophospholipids, sphingomyelin, cholesterol and their derivatives, even though they are found in relatively small amounts in HBM, play an important role in nutrition of developing infants, and play essential roles in all physiological systems and cycles of the human body.
Infants who cannot be breast-fed or who should not receive HBM, or for whom HBM is not available, require breast milk substitutes. The most appropriate alternatives to human milk are infant formulae. Such industrially prepared formulae are based on bovine milk or are derived from a vegetarian source such as soybeans, and try to simulate the composition and biological properties of HBM. These known substitutes attempt to mimic the triglyceride content of HBM.
It is an object of the present invention to provide an improved substitute human milk composition comprising the imperative building blocks found in HMF comprising triglycerides, phospholipids and fatty acids, having benefits associated with mental and physical development of an infant together with benefits associated with intestinal development and function of an infant.